The present invention is particularly intended for use on fuel tanks on commercial vehicles, although it may be used on any fuel tank connected to any type of engine. Fuel tanks typically include a filler tube inlet or opening through which fuel is filled into the fuel tank. On commercial vehicles the fuel tanks may be quite large. Due to high cost of fuel, these large fuel tanks may be susceptible to illegal siphoning of the fuel from the fuel tank.
Siphoning of fuel from a fuel tank generally involves placing a hose through the filler tube inlet or opening and down into the fuel held within the fuel tank. A suction pressure is then applied to the opposite end of the hose such that fuel within the tank flows upwardly and out of the tank through the hose. Siphoning generally cannot be accomplished if the hose cannot be placed downwardly into the tank and into the fuel held within the tank.
In order to prevent siphoning of fuel from fuel tanks, anti-siphon devices have been developed. One such anti-siphon device is described in U.S. Pat. No. 4,630,748, entitled Anti-Siphon Fuel Filler Assembly, wherein a tube is inserted into the tank inlet opening. A lower end of the tube is completely compressed together across the tube's diameter and then welded to form a lower restriction in the tube. Holes are cut or stamped in the lower region of the tube thereby allowing fuel to pass therethrough during filling of the fuel tank. The welded end of the tube generally prevents a hose from being placed downwardly into the fuel tank.
The compressing and welding required for such prior art anti-siphon devices is labor intensive and requires certain manufacturing tools such as heavy duty compressing and welding machines. Accordingly, the prior art manufacturing process results in a device having a relatively large manufacturing cost.
There is a need, therefore, for an anti-siphon fuel filler assembly that can be manufactured without expensive compressing and welding equipment, and which can be manufactured with reduced labor intensive manufacturing steps.